Hydrocarbon oil conversion



Nov. 14, 1933.

c. P. DUBBS HYDBOCARBON OIL CONVERS ION Filed July so, 1927 x Neg? 6%: rbozz fwa bbs;

Patented Nov. 14, 1933 UNITED. STATES 1,935,148 nrnnocaanou OIL convrznsron Carbon P. Dubbs, Wilmette, Ill., assignor to Unl-' versal Oil Products Company, Chicago, 111., a

corporation of South Dakota Application July 30, 1927. Serial No. 209,831 3 Claims. (01. 190-67) This invention relates to improvements in the conversion of heavier hydrocarbon oil into light er oils, and more particularly into products having high anti-knock properties, or products con- 5 taining substantial amounts of aromatic and uns'aturate compounds. j

More particularly, the invention relates to a process wherein the oil is treated in direct contact with combustion gases whereby it is vaporized and converted, and wherein the constituent gases of the combustion assist in the reaction for the production of the hydrocarbons of the characteristics desired.

I am awarethat the treatment of hydrocarbon oils in direct contact with combustion gases has been considered in the prior art, but the processes which have attempted to utilize this method of conversion have not had the advantages which characterize the present invention, 1. e., flexibility and the elimination of the severe conditions of temperature to which the oil was subjected.

To operate this type of process without an extremely high proportion of loss in fixed gases and coke and at the same time to obtain the maximum obtainable proportion of products having the desired boiling point and characteristics, it is necessary that the conditions of operation of the process be regulated to a nicety, and particularly that the degree of heat and temperature to which the oil is subjected in'contact with the combustion gases be so regulated that a relatively mild condition exists, while at the same time the oil and combustion gases are subjected to necessary heat for as long a time as is necessary to produce the degree of conversion desired without utilizing obnoxious temperatures.

These features are present in the process of the invention as will appear more clearlyirom the following description.

It is understood that the process object of the invention may be carried out in a number of ways and in a number of apparatus, but to permit a clear understanding of the invention, I have illus trated in the accompanying drawing two forms of apparatus in which the process may be carried out.

The single figure in the drawing is a diagrammatic view partly in elevation and, partly in section of apparatus in which the invention may be carried out, in which 1 designates a furnace setting which may be of bricksupported by a suitable frame work, which furnace may be divided into four parts by the partitions 5, 5' and 5" to produce a combustion chamber 2, heated by burners 3, wherein combustion of fuel is effected and from which the hot combustion gases pass through flue 4 provided in theupper portion at the furnace setting above partition 5", into preheating chamber 6. In preheating chamber 6 is positioned a preheating coil 7', through which the oil to be treated may be passed, as hereafter described. In chamber 6 may also be positioned coil 6' in which steam to be used in the process,

as will be hereafter described, may be superheated to the desired temperature. Instead of steam, water may be passed through said coil, said water, of course, being vaporized and steam produced. The combustion gases, after passing over said preheating coil 7' and steam coil 6' in the preheating chamber 6, where they are somewhat lowered in temperature, pass out through flue 7 into the lower portion of the third compartment 8 of the furnace, maintained entirely separate from the other compartments, except for the due 7, through the medium of a separating wall or 5 partition 9. The separating wall 9 is preferably made of radiating material so that a portion of the heat of the combustion gases passing through the preheating chamber 6 is radiated into the chamber 8 through the wall 9. It is understood so that the characteristics of the material of which the wall is made and the thickness of the wall may be changed so that the amount of heat radiated through said wall can be controlled.

The material to be treated, which may be crude 88 oil or any fraction thereof or which may be a paste-like mixture of solid hydrocarbon-containing material, such as powdered coal, coal tar and the like, with a controlled proportion of liquid oil, is charged into the system from storage means 90 (not shown) through line 10, and pump 11, from which it maybe diverted into line 12 controlled by a valve 13, and through line 14 into the lower bank of tubes of the preheating coil '7'. The oil passing through the preheating coil '7' is heated to a temperature which is preferably below conversion temperature, and then passed through transfer line 15, controlled by valves 16, into an injecting nozzle or perforated pipe 17, positioned in the chamber 8. The injector or perforated pipe 190 1'7 may be of any desired construction, and the injection of the raw oil may .be confined to one point of the chamber or may be divided over the length of the chamber 8 by extending the injector 17 through the length of said chamber.

As will be noted, the oil passing through the preheating coil 7' may, if desired, be maintained therein under a pressure higher than the pressure maintained in the chamber 8, by means oi. the no pump 11 and valves 16, so that the oil will be preheated while in a substantially liquid form at the temperature required, and will vaporize only when it is injected into the chamber 8.

In said chamber 8, the oil sprayed downwardly through injector 1'7 comes in contact with the ascending combustion gases entering said chamber through line 7. The gases and the oil are thus brought into intimate contact, the oil is vaporized and receives the heat required for conversion from the combustion gases in the chamber as well as from the radiating wall 9.

The hydrocarbon vapors, noncondensible gases and combustion gases from the heating chamber 8, pass oif the top of the chamber through vapor line 18 controlled by valve 19 through which they are discharged into a reaction chamber 20. In the reaction chamber the reaction is completed and the heavier liquid and solid products of the reaction separate and are entrapped.

The heavy quid products, if such are made? are withdrawn, preferably continuously from the reaction chamber 20,- through one or more of the lines 21, controlled by valves 22 and through line 23, controlled by valve 24, and passed to storage or to ether treating zones. Or, these liquid products may be returned to the heating coil '7' and heating chamber 8 for retreatment through line I 25, in which is interposed pump 25a and valve 26, which line is connected with the main charging line 14. The vapors and gases separated in the reaction chamber pass off through vapor line 27 controlled by valve 28 and are directed into dephlegmating column 29, which is provided with suitable fractionating means, such as bubble trays, plates, or the like (not shown), wherein the vaporized products of reaction undergo fractionation. The fractionation may be assisted by introducing therein cooling mediums. For instance, all or any regulated portion of the raw oil from pump 11 can be directed into the top of the dephlegmator 29 through line 30, controlled by valve 31 instead of passing directly to the heating tubes through line 12, or a portion of the raw oil may be passed directly to the heating zone and the other portion may be charged to the dephelgmator.

The reflux condensate and the preheated raw oil which does not vaporize in the dephlegmator are withdrawn from the bottom thereof through the line 32 connected to line 33, which latter is controlled by valve 34, connected at one end with main charging line 14, whereby said condensed products may be returned to the system for retreatment. A pump 35, is interposed in by-pass lines 36 and 3'? controlled by valves 38 and 39 and connected to the reflux line 33, whereby said pump may be utilized to return the oil from the dephlegmator to the heating coil. The line 32 may also be provided with a branch 40, controlled by valve il, whereby any portion of, or all, the oil from the dephlegmator may be withdrawn from the process.

The vapors which have not been condensed in the dephlegmator 29 pass out therefrom through vapor line 12, controlled by valve 43, thence into condenser 44, from which the condensed and uncondensed products are directed into receiver 45 through line 46, controlled by valve 47. The receiver is provided with gas release line 48 controlled by valve 49 and the liquid draw-off 50, controlled by valve 51. If desired, a portion of the liquid products collected in receiver 45 may be returned to the dephlegmator 29, as a cooling agent through line 52, in which may be interposed valve 53, pump 54 and valve 56.

As a. further feature of the invention, a portion of the combustion gases evolved in the combustion chamber 2 of furnace 1 may be withdrawn from the furnace, after they have travelled therethrough for some length, and have thereby been cooled to some degree, and returned to the hottest zone of the combustion chamber relativelyclose to the burners 3. For instance, this can be effected by drawing off a portion of the gases of combustion from the lower end of the preheater chamber, as illustrated in the drawing, through flue 57 on which is interposed a gas pumping means such as a fan 58, whereby this portion of relatively cooler gas is returned into the hottest combustion gases in chamber 2. In this manner it is possible to regulate accurately, by means of the mixture of the relatively colder gas in a controlled amount with the hotter gas of combustion, the tempera- ,Tture of the latter, as well as the composition of the combustion gases through the various parts of the furnace.

In this manner, by combining the control of the temperature and composition of the combustion gases through the recirculation of a portion thereof through flue 5'1 with the control of the amount of heat radiated through the partition 9 and that given to the oil in the preheating coil '7', it is possible to control accurately the temperature and the composition of the combustion gases entering the heating chamber 8 and coming in contact with the oil which is atomized therein, so that the desired results may be produced.

As a further feature of my invention, to combine the proper time element under which the materials undergoing reaction are maintained under proper temperature with the regulation of said temperature, the mixture of combustion gases and vapors and incondensible gases produced in the heating chamber 8 and withdrawn therefrom, are returned, preferably in a continuous manner, to said chamber in a local cycle, for instance, as shown in the drawing through circulating line 59,

controlled by valve 60 and on which is interposed the circulating vapor or gas pump or fan 61.

By controlling the circulation of the vapors leaving the heating chamber 8 by valves 19 and 60, I am able to control to a nicety the length of time during which the oil is subjected to the proper temperature and treatment in contact with the combustion gases.

Although I have shown in the drawing that portions of the combustion gases produced in combustion chamber 2 may be withdrawn from the bottom of the preheating chamber 6 and returned to the hottest zone of combustion within the burners 3, it is understood that the point at which a part of said gas may be withdrawn for recirculating to the combustion chamber can be varied according to the conditions of operation and results desired.

In the same manner the point to which the vapors and combustion gases, withdrawn from chamber 8 are returned may be varied, but they chamber 8 for better efficiency of the heating process.

As a further feature of the invention, steam may be injected into. the material undergoing reaction in the process, the desirability of which will, of course, depend upon the characteristics of the material being treated and the kinds of products desired. For this purpose coil 6', as heretofore described, has been provided and steam formed in said coil or raised while passing therethrough to temperature desired may be passed through discharge line 62 controlled by valves 63 and 65 and injected through nozzle 64 into the mixing or reaction chamber 8. Or, if desired, I provide a connecting line 66 controlled by valve 6''! between the steam discharge line 62 and the oil discharge line 15 whereby, by proper manipulation of the valves 16, 65 and 66, the steam and oil may be combined before entering chamber 8;

As a further feature of the invention it may be desirable to lower the temperature of the combustion gases leaving the preheating chamber 6 through flue '7 before mixing them with the oil in chamber 8, and for this purpose it may be desired to mix said combustion gases with steam to obtain a mixture at the proper temperature before combining with the oil. To accomplish this a portion or all of the combustion gases from chamber 6 may be passed through flue 68 into chamber 69 formed by partitions 5, 5 and 5 and a portion or all of the steam discharged from the coil 6' may be passed to said chamber 69 through line '70 controlled by valve. 70. The temperature of the mixture may be thus regulated and the.

mixture is withdrawn from chamber 69 through flue 71 which connects with flue 7 at an intermediate point thereof whereby the gas and steam mixture is directed to the mixing chamber 8. g

It is understood that the steam, before being combined with the oil and combustion gases may be raised to any desired degree of superheat, and it may be also desirable to decompose said steam into its elements before mixing it with the oil. In some instances the introduction of steam may be used to inhibit a tendency of the oil to burn or explode when in admixture with the combus tion gases due to an excess of oxygen in the latter. Steam when used for this purpose is preferably not decomposed.

A discharge branch line 72 controlled by valve 72' has been provided at the outlet of the steam coil 6' whereby steam passed through said coil may be discharged from the system without mixing with the oil and combustion gases. Burning of the coil 6' may be thus prevented should it be desired to use the process without mixing steam with the material undergoing treatment.

A branch flue 73 may be connected to the flue 57 whereby any portion of the combustion gases may be led directly to the stack without reentering the system, and it is understood that any other gas circulating flue may be provided with such by pass to the stack.

The various fines may also be provided with suitable dampers or cut off valves 74 so that any flue may be cut out or put into operation when desired.

While I have shown that the steam mixed with combustion gases in chamber 69 is led out of said chamber directly to the mixing chamber 8 through fine 71, it may be desirable to submit the steam and combustion gases in said chamber 69 to recirculation to and from said chamber. Suitable fiues with proper dampers and recirculating means (not shown) may be provided. Also suitable recirculating means (not shown) may be provided on the various fiues to permit passages of the materials undergoing treatment from one part of-the process to the other and overcome friction losses and back pressures. a

It can be seen that by means of the processobjeot of the invention the oil can be subjected to the treatment of the combustion gases in intimate mixture therewith at such temperature as is best to produce the desired results. The'composition of the gas in contact with the oil, and particularly the amount of carbon monoxide present in said gas will be governed by the degree of incomplete combustion of the fuel consumed and the rate of recirculation of the fiue gases. The temperature to which the oil is subjected will also be governed by the amount of flue-gas circulated in the combustion chamber as well as the degree of convection and radiation into coil '7' and through partition 9 so that no portion of the oil is subjected to a temperature higher than desired. Furthermore, the circulation of the oil vapors, flue gases and uncondensible gases in admixture from and to the heating chamber 8 should hold this mixture at the desired temperature for the desired length of time and this will depend upon the rapidity of the circulation.

The injection of steam at a suitable temperature is a further feature of the invention permitting temperature control of the material undergoing treatment and thus regulating the characteristics of the products obtained.

I can, by means of this process, and particularly by the control of the temperature of the combustion gases, control the degree of/preheating given to the oil in the coil 7' and I can also control the temperature to which the oil is subjected when discharged into the combustion gases in heating chamber 8.

As another feature of the invention the temperature to which the oil is subjected in the heating chamber 8 is dependent upon the condition of the gas, and particularly the content of carbon monoxide in said gas. In some instances, it may be desired to maintain the temperature in this heating chamber 8 sufliciently high to produce in said chamber a substantial conversion of the oil into gasoline which I find contains antiknock compounds, probably due to reaction between the carbon monoxide and certain of the hydrocarbons.

Anyone skilled in the art will understand that different oils will not react at the same temperature to the same degree, nor that the different fractions of an oil will react at the same temperatures, so that the best conditions suited to the oil being treated will be determined preferably by making a pilot run with the oil being treated.

The pressure maintained on the system or on the various parts thereof will depend upon the characteristics of the material treated, and while I consider maintaining upon the preheating coil 7 a superatmospheric pressure which will prevent substantial vaporization of the oil therein under the temperature used, the balance of the system from the heating chamber 8 on may be preferably operated under atmospheric pressure.

Suitable pumping means may be provided on an inlet to the steam coil 6 whereby water may be furnished thereto under suitable pressure, or should steam be directly used in coil 6' said steam should be at such pressure that it would readily flow through the apparatus. Should a superatmospheric pressure be maintained on the oil heating coil '7' the steam is preferably injected into the material undergoing treatment at a point beyond that where the pressure on said heating coil 7' is reduced to that of the mixing chamber.

When it is necessary, to assist in producing draft for the combustion in the furnace and motion of the vapors and gases through the system, a vacuum pump may be connected to any desired point thereof, for instance, it may be connected to the receiver 45 or to the outlet of the condenser 44.

While I have described heretofore a method suitable for carrying out the invention under atmospheric or subatmospheric pressure, it may be desirable to operate under superatmospheric pressure, particularly, for instance, when production of aromatic hydrocarbons is desired. While the concept of the invention will remain the same, the apparatus to carry it out may be somewhat modified, for instance, the mixing chamber 8 as well as other parts of the apparatus may be preferably encased in pressure-resisting metallic casing of any desired shape, and suitable pumping means may be utilized on the various parts of the system to permit maintaining in chamber 8 and on the balance of the system proper pressure.

When the oil which is treated contains sulphur which forms products which would corrode the system and form objectionable compounds in the distillates and gases, I may add to the oil a caustic material such as lime, sodium, potassium, barium or the like, either in pulverized form, or as an aqueous solution. This caustic material may be added to the oil before it enters the heating chamber 8.

In this manner, the caustic is brought into intimate contact with the fine particles of the oil atomized through nozzle or perforated pipe 17, and the reaction between the caustic and the sulphur or sulphur compounds is more complete.

In another method of operation, water-gas or producer gas may be injected into the heating chamber 8, or at any point in the passage of combustion gases through the furnace 1, whereby additional reaction will occur, causing enrichment of the producer gas and formation of aromatic, ethylenic, alkyl compounds and the like.

Depending upon the results desired the partitions 5, 5' and 5" may be built either with refractory material or with heat radiating material. In all instances the temperature of the steam discharged into chamber 69 should be such that when admixed with the combustion gases of said chamber and after receiving radiant heat from partitions 5, 5' and 5", if these partitions are radiating wallsythe temperature of the admixture of steam and combustion gases is that desirable for the reaction in chamber 8.

While I have illustrated and described the use of the flue gas generated in chamber 2 to heat the oil to be treated in coil 7', the aforesaid gas being mixed with said oil in chamber 8, it is well within the scope of my invention to dispense with the steam and oil heating coils 6' and 7 in the chamber 6, and to use chambers 2 and 6 only for generating flue gas to be used in the process and to regulate the temperature of the gas at the outlet of chamber 6, as heretofore described. The oil and steam can then be heated or generated in coils positioned in one or more separate heating zones, the flue gases of which are evacuated to means a stack without entering the process. The heated oil may then be injected to chamber 8, as here= tofore described, and the steam may be combined with the combustion gases to be used in the process in chamber 69 or in chamber 8, or it may be combined with the oil at the outlet of the separate oil heating coil, or it may be entirely dispensed with.

-I. claim as my invention:

1. A process for converting hydrocarbons, which comprises first subjecting said hydrocarbons to indirect heat conductive relationship with heated gases of combustion in a heating zone, and then bringing said hydrocarbons into direct contact with highly heated steam and said combustion gases in a conversion zone to cause conversion and substantial vaporization, removing the vapors. controlling the conditions of temperature so that no substantial overheating of said hydrocarbons takes place by causing local circulation of regulated portions of said combustion gases to and from said heating zone, and controlling the degree of conversion taking place by recirculating through the conversion zone regulated portions of the vapors removed from said conversion zone.

2. A process for converting hydrocarbons, which comprises raising the temperature of said hydrocarbons by subjection in a heating zone to indirect heat conductive relationship Withcombustion gases, subsequently passing the heated hydrocarbons to a conversion zone and subjecting the same therein to direct contact with said combustion gases and with highly heated steam to cause substantial vaporization and conversion, removing the vapors and subjecting same to dephlegmation in a dephlegmating zone, removing reflux condensate from the dephlegmating zone and returning same to the heating zone for retreatment, and controlling the degree of conversion taking place, by locally recirculating through the conversion zone regulated portions of the vapors passing to said dephlegmating zone.

3. A process for converting hydrocarbons, which comprises raising the temperature of said hydrocarbons by subjection in a heating zone to indirect heat conductive relationship with combustion gases, subsequently passing the heated hydrocarbons to a conversion zoneand subjecting the same therein to direct contact with said combustion gases and with highly heated steam to cause substantial vaporization and conversion,

removing the vapors and subjecting same to;

dephlegmation in a dephlegmating zone, removing reflux condensate from the dephlegmating zone and returning same to the heating zone for retreatment, controlling the degree of conversion taking place by locally recirculating through the CARBON P. DUBBS. 

